[llvm] [AMDGPU] Add pre-commit tests for PR90710. NFC. (PR #90711)

[Jay Foad via llvm-commits]

jayfoad wrote:

Can you just make this the first commit in #90710? Then reviewers can see the effect that the patch has on this test by looking at the two commits individually (but when you merge it it'll all get squashed into a single commit which is OK).

https://github.com/llvm/llvm-project/pull/90711